Yea, Me not likeing to make a pt late at night I tried to solo these as a 70SMN/35WHM and I was able to do it with a bit of ease, I used the basic kitting strategy (yes I have free carby). I was able to take down one every 8-12 mins Is my guess of the time. The major problem though was that after I took down the 2nd one by the time I started attacking (or soon after) the 3rd the first one would re-spawned.
Anyways. . I gave up for tonight always being 2out/2up and not really able to see a way around it. I will more then likely try and find a smn friend/and or bst friend that will help me with this.
Good luck yall and happy hunting ^^
(oh yea fyi I got around 43exp at lvl 70 from these)
the reason you found them and "impossible to gauge" is because they are for windurst mission 7-1 "The Sixth Ministry" you have to kill these 4 before you can open the marble door and flag the cutscene inside.